238 research outputs found
From the Greek theater to the mind: the opportunities of the mask
From some elements of the mask in the ancient Greek theatre which are expressed in the current civilization and psychic economy, it is possible to identify positive some psychological functions that can be performed by the mask, especially the self-protection and the possibility to put into play unknown parts of the self, therefore meeting the diveristy within and outside us. It's highlighted how the ongoing simplification in the mask could on one side offer a supporting screen in a society that multiplies images and amplifies the fragmentation risk, and on the other could reduce the risk of distortions of one ownâs image in the otherâs eyes. Therefore, the problem of believable speakers on which one could put his epistemophilic trust is arised and this is linked to the theme of openness to the future, to the persistence and the necessity of sharing, of relationship. Namely, itâs highlighted the possibility offered by the mask of experimenting what is not yet, but is present in the desire, as a sort of anticipating background that, instead of being closed in a mental fantasy or in a daydream, is played in the reality (virtual?). It's underlined how this function stays in a delicate balance between experimentation â the âcarnivalâ function â and the gamble and its collocation could therefore fluctuate between the work-in-progress frame and the suicidary one, in which parts of the self can be integrated rather than reduced. Finally, highlighting the dimension of beauty and culture, recalled from the Greek theatre mask, itâs adfirmed the importance of these values, translated as play and care systems, a transitional space, in the psychological and psychotherapy fields. The explained themes are lastly evoked and exemplified through the illustration of a clinical case
A 20 GHz bright sample for {\delta} > +72{\deg}: I. Catalogue
During 2010-2011, the Medicina 32-m dish hosted the 7-feed 18-26.5 GHz
receiver built for the Sardinia Radio Telescope, with the goal to perform its
commissioning. This opportunity was exploited to carry out a pilot survey at 20
GHz over the area for {\delta} > + 72.3{\deg}. This paper describes all the
phases of the observations, as they were performed using new hardware and
software facilities. The map-making and source extraction procedures are
illustrated. A customised data reduction tool was used during the follow-up
phase, which produced a list of 73 confirmed sources down to a flux density of
115 mJy. The resulting catalogue, here presented, is complete above 200 mJy.
Source counts are in agreement with those provided by the AT20G survey. This
pilot activity paves the way to a larger project, the K-band Northern Wide
Survey (KNoWS), whose final aim is to survey the whole Northern Hemisphere down
to a flux limit of 50 mJy (5{\sigma}).Comment: 10 pages, 10 figures. Accepted by MNRA
Detection of new point-sources in WMAP Cosmic Microwave Background (CMB) maps at high Galactic latitude. A new technique to extract point sources from CMB maps
In experimental microwave maps, point-sources can strongly affect the
estimation of the power-spectrum and/or the test of Gaussianity of the Cosmic
Microwave Background (CMB) component. As a consequence, their removal from the
sky maps represents a critical step in the analysis of the CMB data. Before
removing a source, however, it is necessary to detect it and source extraction
consists of a delicate preliminary operation. In the literature, various
techniques have been presented to detect point-sources in the sky maps. The
most sophisticated ones exploit the multi-frequency nature of the observations
that is typical of the CMB experiments. These techniques have "optimal"
theoretical properties and, at least in principle, are capable of remarkable
performances. Actually, they are rather difficult to use and this deteriorates
the quality of the obtainable results. In this paper, we present a new
technique, the "weighted matched filter" (WMF), that is quite simple to use and
hence more robust in practical applications. Such technique shows particular
efficiency in the detection of sources whose spectra have a slope different
from zero. We apply this method to three Southern Hemisphere sky regions - each
with an area of 400 square degrees - of the seven years Wilkinson Microwave
Anisotropy Probe (WMAP) maps and compare the resulting sources with those of
the two seven-year WMAP point-sources catalogues. In these selected regions we
find seven additional sources not previously listed in WMAP catalogues and
discuss their most likely identification and spectral properties.Comment: Astronomy and Astrophysics, 2011, in pres
High--frequency predictions for number counts and spectral properties of extragalactic radio sources. New evidences of a break at mm wavelengths in spectra of bright blazar sources
We present models to predict high frequency counts of extragalactic radio
sources using physically grounded recipes to describe the complex spectral
behaviour of blazars, that dominate the mm-wave counts at bright flux
densities. We show that simple power-law spectra are ruled out by
high-frequency (nu>100 GHz) data. These data also strongly constrain models
featuring the spectral breaks predicted by classical physical models for the
synchrotron emission produced in jets of blazars (Blandford & Konigl 1979;
Konigl 1981). A model dealing with blazars as a single population is, at best,
only marginally consistent with data coming from current surveys at high radio
frequencies. Our most successful model assumes different distributions of break
frequencies, nu_M, for BL Lacs and Flat-Spectrum Radio Quasars (FSRQs). The
former objects have substantially higher values of nu_M, implying that the
synchrotron emission comes from more compact regions; therefore, a substantial
increase of the BL Lac fraction at high radio frequencies and at bright flux
densities is predicted. Remarkably, our best model is able to give a very good
fit to all the observed data on number counts and on distributions of spectral
indices of extragalactic radio sources at frequencies above 5 and up to 220
GHz. Predictions for the forthcoming sub-mm blazar counts from Planck, at the
highest HFI frequencies, and from Herschel surveys are also presented.Comment: 21 pages, 16 figures; Eq.B.2 and labels in few Figures correcte
The Luminous Blue Variable RMC127 as seen with ALMA and ATCA
We present ALMA and ATCA observations of the luminous blue variable \rmc. The
radio maps show for the first time the core of the nebula and evidence that the
nebula is strongly asymmetric with a Z-pattern shape. Hints of this morphology
are also visible in the archival \emph{HST} image, which overall
resembles the radio emission. The emission mechanism in the outer nebula is
optically thin free-free in the radio. At high frequencies, a component of
point-source emission appears at the position of the star, up to the ALMA
frequencies. The rising flux density distribution () of this object suggests thermal emission from the ionized
stellar wind and indicates a departure from spherical symmetry with
. We examine different scenarios to explain this excess
of thermal emission from the wind and show that this can arise from a bipolar
outflow, supporting the suggestion by other authors that the stellar wind of
\rmc is aspherical. We fit the data with two collimated ionized wind models and
we find that the mass-loss rate can be a factor of two or more smaller than in
the spherical case. We also fit the photometry obtained by IR space telescopes
and deduce that the mid- to far-IR emission must arise from extended, cool
() dust within the outer ionized nebula. Finally we discuss two
possible scenarios for the nebular morphology: the canonical single star
expanding shell geometry, and a precessing jet model assuming presence of a
companion star.Comment: Accepted for publication in ApJ (minor revision included
Italian Science Case for ALMA Band 2+3
The Premiale Project "Science and Technology in Italy for the upgraded ALMA
Observatory - iALMA" has the goal of strengthening the scientific,
technological and industrial Italian contribution to the Atacama Large
Millimeter/submillimeter Array (ALMA), the largest ground based international
infrastructure for the study of the Universe in the microwave. One of the main
objectives of the Science Working Group (SWG) inside iALMA, the Work Package 1,
is to develop the Italian contribution to the Science Case for the ALMA Band 2
or Band 2+3 receiver. ALMA Band 2 receiver spans from ~67 GHz (bounded by an
opaque line complex of ozone lines) up to 90 GHz which overlaps with the lower
frequency end of ALMA Band 3. Receiver technology has advanced since the
original definition of the ALMA frequency bands. It is now feasible to produce
a single receiver which could cover the whole frequency range from 67 GHz to
116 GHz, encompassing Band 2 and Band 3 in a single receiver cartridge, a so
called Band 2+3 system. In addition, upgrades of the ALMA system are now
foreseen that should double the bandwidth to 16 GHz. The science drivers
discussed below therefore also discuss the advantages of these two enhancements
over the originally foreseen Band 2 system.Comment: 43 pages, 21 figure
ALMA reveals a warm and compact starburst around a heavily obscured supermassive black hole at z=4.75
We report ALMA Cycle 0 observations at 1.3mm of LESS J033229.4-275619
(XID403), an Ultraluminous Infrared Galaxy at in the Chandra Deep
Field South hosting a Compton-thick QSO. The source is not resolved in our data
at a resolution of 0.75 arcsec, placing an upper-limit of 2.5 kpc to the
half-light radius of the continuum emission from heated-dust. After
deconvolving for the beam size, however, we found a indication of
an intrinsic source size of arcsec (Gaussian FWHM), which would
correspond to kpc. We build the far-IR SED of XID403 by
combining datapoints from both ALMA and Herschel and fit it with a modified
blackbody spectrum. For the first time, we measure the dust temperature
K in this system, which is comparable to what has been
observed in other high-z submillimeter galaxies. The measured star formation
rate is SFR= yr, in agreement with previous
estimates at lower S/N. Based on the measured SFR and source size, we constrain
the SFR surface density to be yrkpc
(yrkpc for kpc). The
compactness of this starburst is comparable to what has been observed in other
local and high-z starburst galaxies. If the gas mass measured from previous
[CII] and CO(2-1) observations at low resolution is confined within the same
dust region, assuming kpc, this would produce a column
density of cm towards the central SMBH,
similar to the column density of cm measured
from the X-rays. Then, in principle, if both gas and dust were confined on
sub-kpc scales, this would be sufficient to produce the observed X-ray column
density without any need of a pc-scale absorber [abridged].Comment: 11 pages, 5 figures. Accepted for publication in A&
A polarization survey of bright extragalactic AT20G sources
We present polarization data for 180 extragalactic sources extracted from the Australia Telescope 20âGHz (AT20G) survey catalogue and observed with the Australia Telescope Compact Array during a dedicated, high sensitivity run (ÏP ⌠1âmJy). For the sake of completeness, we extracted the polarization information for seven extended sources from the 9âyr Wilkinson Microwave Anisotropy Probe co-added maps at 23âGHz. The full sample of 187 sources constitutes a â99 perâcent complete sample of extragalactic sources brighter than S20GHz = 500âmJy at the selection epoch with declination ÎŽ < â30°. The sample has a 91.4 perâcent detection rate in polarization at âŒ20âGHz (94 perâcent if considering the subsample of point-like sources). We have measurements also at 4.8 and 8.6âGHz within âŒ1 month of the 20âGHz observations for 172 sources to reconstruct the spectral properties of the sample in total intensity and in polarization: 143 of them have a polarization detection at all three frequencies.
We find that there is no statistically significant evidence of a relationship either between the fraction of polarization and frequency or between the fraction of polarization and the total intensity flux density. This indicates that Faraday depolarization is not very important above 4.8âGHz and that the magnetic field is not substantially more ordered in the regions dominating the emission at higher frequencies (up to 20âGHz). We estimate the distribution of the polarization fraction and the polarized flux density source counts at âŒ20âGHz
Selecting a complete sample of blazars in sub-millimetre catalogues
The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS), which has covered about 642 sq. deg. in five bands from 100 to 500 mu m, allows a blind flux-limited selection of blazars at sub-mm wavelengths. However, blazars constitute a tiny fraction of H-ATLAS sources and therefore identifying them is not a trivial task. Using the data on known blazars detected by the H-ATLAS, we have defined a locus for 500 p.m selected blazars and exploited it to select blazar candidates in the H-ATLAS fields. Candidates and known blazars in the H-ATLAS equatorial and South Galactic Pole fields were followed up with the Australia Telescope Compact Array (ATCA) or with the Karl G. Jansky Very Large Array (VLA), and matched with existing radio- and mm-catalogues to reconstruct the spectral behaviour over at least six orders of magnitude in frequency. We identified a selection approach that, combining the information in the sub-mm and radio domains, efficiently singles out genuine blazars. In this way, we identified a sample of 39 blazars brighter than S-500 mu m = 35 mJy in the H-ATLAS fields. Tests made cross-matching the H-ATLAS catalogues with large catalogues of blazar candidates indicate that the sample is complete. The derived counts are compared with model predictions finding good consistency with the C2Ex model and with estimates based on ALMA data
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